Laboratory-furnace.



C. A. PFANSTIEHL.

, LABORATORY FURNACE.

APPLICATION FILED JULY i1- I9I6. 1,283,285. Patented 0@t.29,1918.

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C. A. PFANST-EHL.

LABORATORY FURNACE.

APPLlcATloN FILED :uw 11.1915.

1,283,285.v Patented o@t.29,1918.

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C. A. PFANSTIEHL.

LABORATORY FURNACE.

APPLICATION FILED IuLY I1. IeIe.

Patented Oct. 29, i918.

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UNITED STATES PATENT OFFICE.

CARL A. PFANSTIEHL, OF HIGHLAND PARK, ILLINOIS, ASSIGNOR TO PFANSTIEHL COMPANY, INC., OF NORTH CHICAGO, ILLINOIS, A CORPORATION OF NEVI YORK.

LABORATORY-FURNACE;

Specification of Letters Patent.

Patented Oct. 29, 191'8.

T all whom t may concern.'

Be it knownthat I, Gann A. PFANSTIEHL, a citizen of the United States, and a resident of Highland Park, in the county of Lake and State ofY Illinois, have invented certain new and useful Improvements in Laboratory-Furnaces, of which the following is a clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of the specification.

My invention relates to an electric furnace equipped` with heating, cooling, electrical and mechanical devices, so that the'furnace ma)Y be used for a large variety of purposes to meet the requirements of an experimental or development laborat-cry. Many features of in v invention are also of utility` in the manufacture of chemicals or compositions of matter in a commercial way, though it is unnecessaryv that all ofthe features of my invention be incorporatedv in a commercial embodiment designed for the accomplishnient of one specific end or the manufacture of one specific substance.

The objects of my invention are the provision of a furnace which may be readiljv and quickly opened and closed, and which, without the loss of time or the exertion of great effort on the part of the operator, becomes perfectly sealed against the passage of atmosphere to or from the furnace when the furnace is closed; the provision of perfcctly sealed joints for leading in electrical conductors and movable shafts ,j the provision of a suitable electrically heated crucible; the provision of water cooled and adjustable supports for the heating element, and the provision of suitable supporting and controlling mechanism for the furnace and its cover. Another object of the invention is the provision of one or more observation windows and particularly the means provided for preventilrg` breakage of the glass by heat, and for sealing around the glass to prevent the passage of air or gas.

Still further features of the invention will be pointed out in the followingdetailed description and claims.

My invention is illustrated in the accompanying drawings, in which- Figure l is an elevation of the furnace and supporting frame; Y

Fig. 2 is a plan of the furnace and its supporting frame;

Fig. 3 is a vertical section through the furnace taken on the line 3-3 of Fig. 2;

Fig. I is a plan view of the furnace with cover removed;

Fig. 5 is a section through one of the side observation windows;

Fig. 6 is a detailed sectional view of the mechanism for leadingl in electrical conductors or binding posts;

Fig. 7 is a detailed sectional view of the mechanism for leading in rotatable or oscillating shafts; and

Fig. 8 isa section taken on the line S-S of F ig'. 3, and showing the structure of the movable heating element support.

I preferably7 supportmy furnace upon a platform l, mounted in a suitable manner upon rollers or casters 2. Extending vertically from the platform l are six uprights -l preferably of pipe. These uprights are united at their upper ends by means of pipe sections 5 and couplings G, so as to form a rigid structure for the support of the furnace cover lifting and adjusting mechanism. This lifting and adjusting mechanism is preferablyv in the form of a windlass provided with two short drums 8 and 9, to which a pair of cables 10 are attached, thc latter passing over suitabl)y supported pulleys ll and l2 and being attached at the other end to the furnace cover I3.

The base lel of the furnace is held at a convenient height above the platform 1 by means of a pair of columns l5, these columns being rigidly attached both to the base ll and to the platform l. This base member ldshown in section in Fig. 3 comprises upper and lower walls and a pluralityT of spacing webs I6. by means of which a chamberis provided for the circulation of water or other cooling substance. The spacing web 1G as illustrated in Fig. 4 extends only partiallyv across the base member, thus facilitating the circulation of the cooling fluid which enters and escapes from the base chamber through the lead-in and exhaust pipes 19 and 20.

Around the periphery of the furnace base la is a channel 21, the base of which is` provided with a pair of circumferential ridges 22, the apeXes of which are comparativeliv sharp so as to press themselves into the circumferential rubber or liber gasket 23 which is carried upon the lower face of the walls of the furnace cover 13. The channel 2l contains mercury, oil, or some other suitable sealing fluid which normally stands at such a level as to be slightly above the apeXes of the ridges 22. W'hen the cover 13 isbrought into place the sealing fluid rises slightly' true of the main electrical terminals 25 and' 26. It has been found impracticable tol produce an absolutely non-leakingV insulating joint between electrical conductors and the furnace walls without the aid of oil or some other sealing fluid. :fn accordance with my invention there is provided an oil pan 30 which is attached to and extends beneath the furnace base 14, Aand which is adapted to contain oil to a level above the external openings in the base let through which the conductors` 25 and 26 extend. This pan is a tached to the furnace base la by any suitable means such as soldering.

Each of the conductors 25 and 26 is provided with a water circulating duct 31 through which water is caused to iiow by forced feed to prevent an abnormal rise in temperature of the electrodes or heating element supports. The electrode support 26 is provided with a bridgemember 38 through which a set screw 34k extends for clamping the conducting lock 35 upon the heating element or other device which is to be supiorted between the terminals 25 and 26. lnv l order that the expansion and contraction of the heated element will be taken up the electric terminal 25 is provided with a sliding member 37 which tits upon .the horizontal portion of the ,terminal 25 with a dove tail connection, as shown in Eig. 8. The parts 25 and 37. are preferably made of copper and the contacting surfaces between these parts are made large so that the heat will be quickly conducted away from the movable portion 37 by the cooler portion 25. ln view of the factthat very heavy currents are sometimes used in my furnace I do not depend upon the Contact between the elements 25 and 37 for the electric circ-uit, but provide flexible conductors 38, so arranged as to offer very slight resist-anceto the movementcof the member 3T upon the member 25. These conductors are clamped in good electrical connection with the members 25 and 37, and may also, ifdesired, be soldered thereto. to decrease thei-y contact resistance. A small spring a() is provided so that a heating element maybe supported between the electrical terminals merely by the` end pres sure exerted by the spring fi() on the vmovable terminal ,37. This expedient is resorted to in sintering ingots of compressed metal by use of the current for the reason that the ingot in being sintcrcd materially contracts, thus making necessary the automatic 'followup movement of the terminal 37.

. The furnace cover 13 is constructed with inner and outer walls, the space between being filled with water or other cooling fluid which is kept in circulation by a forced feed of liquid through ythe intake and exhaust pipes 4t2 and 4S. Extending axially above the center of the cover is-a projection 4, which supports an observation,V window t5. This window, Vwhichis preferably of glass, is clamped bymeans yof screwset against two soft gaskets a7 and i8. These gaskets are so positioned as to provide an annular space between them which is preferably filled with mercury to form a seal which is impenetrable by air or gases. By positioning the window'l at some distance above the heated element of the furnace and at the extremity'of a chamber which is `thoroughly water cooled by water circulated through the intake andk exhaustrpipes 49 and -t9, l am able to eliminate the breakage of the glass even vthough the temperature of the heated element is raised -to several thousand degrees Fahrenheit. l preferably provide other observation windows such as shown in- VTEig; 5 at one or more points through the vertical walls ofthe cover. The structure'of these windows is the same as described for the-window et, excepting that preferably provide a duct 50 through which to iill thev mercury chamber 5l after the glass has been secured in place.

I have herein illustrated onev of the spe cific devices for which my electric furnace is designed. This device is a carbon heating element', the central portion of which is cupped out to form a receptacle in which a Crucible of platinum or porcelain may be placed for heating or.in which such substances as are non-conductors when hot may be directly heated. l have found it preferable to neel; the carbon element 5B adjacent the cupped portionso as to concentrate the greatest heating effect at the receptacle. The method of'necling is illustrated at 5a in Fig. 3.

In order'that my furnace may belused for a great variety of purposes and in order that a plurality Iof electric circuitsmay be provided by means of which various electrically controlled devices may be' operated within the furnace I provide `Ya plurality yof conductingV elements 56 which extend through apertures in the base of the' furnace and to which conductors may be attached both outside and within'thefurnace chamber. Each of these electric leads is insulated and sealed as illustrated in Fig 6. The conductor 58 is surrounded within the base portion by` cement 59, which is poured in place about the conductor after the nuts 50 have been clamped upon the insulating washers 6l. In

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order to make a perfect seal a cup 62 containing oil is threaded upon the lower end of the conductor 58.

It sometimes becomes necessary to stir, fan, saw or perform some other mechanical operation upon some part which is being threaded within the furnace chamber. To facilitate such mechanical operations as may be desired I provide a plurality of rotatable shafts 63, which extend through they base portion and which are provided with gears and pulleys to facilitate the application of power thereto. rI`he method of carrying these rotatable shafts through the base member is illustrated in F ig. 7. In this figure it will be seen that the block 65 constitutes the principal bearing for the shaft G3. A' shoulder 66 on this block is clamped against the underside of the base by means of the nut G7, the same type of mercury seal being provided for this block as for the observation windows. rIhe block 65 is provided at its external end with a chamber 68 for the reception of mercury which is confined byjmeans of the threaded plug 69 and the rubber washers 70. The inner end of the plug 65 is provided with a similar but somewhat smaller aperture 72, which contains a piece of oily felt, the oil serving to preserve the lubrication of the shaft. Carried upon the shaft and rotatable therewith is a cup 73 for the reception of mercury to a level above the joints between the plug 69 and the sleeve 65.

In order that water, gases or other fluids may be carried into and out of the chamber of the furnace during its operation I provide a number of tubular connections 7 5 which may be used in an obvious manner for the purposes above described.

From the foregoing detailed description it will be seen that my furnace is capable of a great variety of uses, for example, it may be used as a reducing furnace by providing a. suitable hydrogen atmosphere for bringing about the chemical reduction of an oxid; it may be used as a sintering furnace by passing a heavy current through an ingot of compressed metal in the presence of hydrogen or in a vacuum or rarefied atmosphere as may be required; it may be used for quantitative analysis Where it is desired to determine accurately the quantity of oxygen, hydrogen or other gas which unites with some other gas or chemical under the influence of heat; it may be -used for bringing about the Weld or union of metals which do not readily unite in the presence of air even when heated to their melting point; it may be used for making compounds of metals which have to be mechanically stirred at very high temperatures. In fact, it may be used for almost any purpose in which materials are to be acted upon or observed at high temperatures.

'beneath the base member Although my invention is herein described with reference to the details of a specific embodiment thereof it is to be understood that many of these may be varied or entirely omitted without departing from the spirit or scope of the invention.

W hat I claim as new and desire to secure by Letters Patent of the United States, is:

l. A laboratory device comprising a substantially horizontal base member having a groove in its upper surface, a hollow cover member adapted to fit within the groove in the surface of the base member, sealing fluid within the groove. a water jacket for the cover member, and flexible intake and exhaust pipes for the water jacket whereby the cover member may be raised and lowered from the base member without interrupting the circulation of water through the water jacket.

Q. In a laboratory device the combination with a substantially horizontal base member of a hollow cover member, a frame within which said cover member is located, means carried by said frame for lifting the cover member from the base member, intake and exhaust ports extending through the base member whereby gas or other fluid may be introduced into the inclosure and withdrawn therefrom through permanently fixed piping.

8. In a laboratory apparatus the combination with a base member of a. water jacket therefor, a pair of electrical terminals extending' above the base member and having openings therein for the circulation of cooling fluid, hollow electric conductors extending through the base member, and a pan and containing a non-conducting sealing fluid to prevent leakage by the electric conductors where they pass through the base member, and a cover for the base member inclosing said electrical terminals.

at. A laboratory apparatus comprising a base member, a cooling jacket therefor, electrical conductors extending through the base member and having terminal portions above and below said base member, and a cup carried by each of said conductors and adapted to contain an insulating sealing fluid for preventing the passage of gas by the conductor where it passes through the base member, and a box-like cover member providing a chamber above the base member.

5. In an electric furnace the combination with a base member of an electrically heated element carried thereby, a cover member having water jacketed sides and top, an observation window through the top of the cover member, said window being displaced above the top of the cover member, and a Water j acketed carrier extending between the window and the top of the cover member whereby the glass of the window is protected from IIO the extreme heat of the furnace by a column of wat-ei Cooled gas.

6. An observation window for electric furnaces comprising a transparent member,

means to clamp the transparent member parent material, said gaskets being so placed as to form a duct between them, a sealing fluid in said duct, and means to hold the transparent material rinly against said gaskets. l Y

S. A laboratory device comprising a base member and a box-like cover, a channel in the base member into which the lower edge of the box-like cover extends, a sharp topped continuous ridge carried by the base member, a yielding gasket carried by the cover member and adapted to enga-ge the sharp topped ridge of the base member, and sealing fluid within the channel of the base meinber and entirely covering the point of contact between the cover member gasket and the ridge of the base member.

9. A laboratory device comprising a base member and a box-like Ycover member, a channel in the base member, a kiiife-edge carried by one of said members and being continuous throughout the point of union between the base member and the cover member and a yielding gasket carried by Vthe other of said members and also being continuous throughout 'the point of union ofY the base member and the cover member, said gasket and said knife-edge being brought together when the cover is in place, and a sealing fluid within the channel in thel base member and continuously engaging the point of Contact of said knife edge with said gasket.

10. A laboratory device comprising a base member and a removable cover member, a

Copies of this patent may be obtained for window lfor Vhigh temrotatable shaft extending through the base member, a sleeve surrounding said shaft, a chamber within said sleeve and surrounding said shaft, sealing fluid in said chamber, anda flexible gasket for preventing the sealing fluid from passing along the shaft froml said chamber.

11. A laboratoryV device comprising a base said shaft sealing fluid in said chamber, a`

.i flexible gasket for preventing the sealing fluid from passing along the shaft from said chamber, a collar in said sleeve, an annular vchamber in said collar, and sealing fluid insaid chamber to prevent the passage of gas between the base member and the sleeve. p,

12. ln an electric furnace the combination with a pair of terminals of a-,resistaiice element extending horizontally between said terminals, a cup' in said resist-ance ele-ment, and a neck in the heating element adjacent each side of said cup whereby the heating effect of the element will be concentrated in the cup, one of said terminals having a horizontal Vsliding movement whereby the heat-V ing element may expand and contract without placing it under undue strain andwithout affecting the electrical connection therewith.

and removable cover, electrical conductors extending through said base, a rotatable shaft extending through said base, intake and exhaust pipes to conduct gases to and .from the hollow portion of the device, and

ve cents each, by addressing the Commissioner of Patents,

Washington, I). G.

13. A laboratory device comprising a baseV 

